Expandable articulated tandem roller

ABSTRACT

A roller, particularly for finishing a bituminous mat surface, consists essentially of a pair of roller assemblies each of which is pivoted to and supports one end of a body connecting the two. The roller assemblies can be alternately adjusted and steered by respective pairs of rams controlled from one of two operator stations so that the two roller assemblies proceed in tandem or varying degrees of echelon relation to each other as the roller travels the ground. Each roller assembly includes two rolls, a diagonally opposite pair with respect to the longitudinal axis of the body of the rolls of both assemblies being hydraulically driven while the other diagonally opposite pair is free to rotate independently of the first pair.

United States Patent 1 91 [11] 3,868,194 Ferguson et al. Feb. 25, 1975 [54] EXPANDABLE ARTICULATED TANDEM 3,229,602 H1966 Vivier 404/ I26 2.422 22% x122; 422/12:

, ec [75] Inventors: Edgar J- Ferguson; Harry J- 3,412,659 11/1968 Harbke 404/121 Vonderheide, both of Sacramento; J f Ferguson, Carmichael all Of Primary Examiner-Nile C. Byers, Jr. Calif Attorney, Agent, or FirmHavcn E. Simmons; James [73] Assignee: Iowa Manufacturing Company, Nemmers Cedar Rapids, Iowa [22 Pl d' F b 6 1974 [57] ABSTRACT 1 i e A roller, particularly for finishing a bituminous mat [21] Appl. No.: 440,044 surface, consists essentially of a pair of roller assemblies each of which is pivoted to and supports one end of a body connecting the two. The roller assemblies [52] Cl 404/126 280/442 can be alternately adjusted and steered by respective [51] Int Cl E01 c l9/26 pairs of rams controlled from one of two operator sta- [58] Fie'ld 126 121 tions so that the two roller assemblies proceed in tandem or varying degrees of echelon relation to each 406/132 180/20 280/442 72/518 other as the roller travels the ground. Each roller assembly includes two rolls, a diagonally opposite pair [56] References cued with respect to the longitudinal axis of the body of the UNITED STATES PATENTS rolls of both assemblies being hydraulically driven l,369,977 McLaren the other diagonally opposite pair is free to g; tate independently of the first pair. 311831804 /1965 Le Tourneau 404/121 Claims, 11 Drawing Figures 47 m lllllllllllllllllllllm 84ll alllll 8| b T vs I b BI as a5 8 53 .7; -s $i 3 77 .4 84

2 a so 82 I 75 38" 93 d2 42 a2 6 53 I400 u D 122 142 Ho 52 I03 5O 52 f 102 148 ,Old 21 Om RF RD 2 22 I00 PATENTED 3.868.194

SHEET 3 0F 8 FIG 3 T o O O to PATENTEB FEBZS I975 SHEET t 0F 8 FIG PATENIED FEB 2 5 H75 SHEET 8 0f 8 EXPANDABLE ARTICULATED TANDEM ROLLER BACKGROUND AND OBJECTS OF THE INVENTION The concept of an expandable, articulated tandem roller is revealed, for instance, in US. Pat. Nos. 2,l 32,107 and 3,299,602 in which roller assemblies or the like at each end of a connecting body are each steerable so that the two are in tandem or in varying degrees of echelon relation to each other as the roller proceeds in either direction. This permits the effective width of the roller to be adjusted to fit a wide range of requirements, the width being at a minimum when the two roller assemblies are in tandem and at maximum when the two are in echelon and just overlap each other with respect to the direction of travel. Thus one machine can perform in a single pass what would require two passes by a conventional roller of the same minimum width, or wider conventional rollers, as well as accommodate all widths in between.

If the roller is self-propelled, as is usually the case, its propulsion in either direction is most readily achieved by driving one or both of the roller assemblies. Expansion of the roller is produced by appropriate turns of the roller assemblies. While doubtless both the latter could be turned and steered at the same time, obviously it is easier if they are alternately turned and steered especially when the roller is being expanded or contracted. In the latter case, if only one roller assembly is driven, as is customary in other types of rollers having a pair of roller assemblies, the roller will be really satisfactory only when operating in the tandem mode. This is because if the two roller assemblies are alternately turned to expand or contract the roller, scuffing by the undriven roller assembly will likely result, and perhaps also by the driven roller assembly, even should one or both roller assemblies employ split rolls. Scuffing probably stems from the fact that the couple action involved is impaired if only one roller assembly is driven. Even should both roller assemblies be driven, impairment of the couple action and consequent scuffing would likely occur if the drive for both is laid out in conventional manners or as may be indicated in the foregoing two patents. Prevention or minimizing of scuffing is important when the roller, as is the one of the present invention, is designed especially for finishing of bituminous roadways since scuffing will produce tears in the. mat. Hence, the chief object of the present invention is a drive arrangement for a roller of the nature concerned which prevents or minimizes scuffing when the roller assemblies are alternately turned to expand or contract the roller.

Another object of the present invention is to provide a steering system for a roller of the kind described which permits its two roller assemblies to be alternately steered by a single steering control in order to direct the machine along the ground in either direction and also to expand and contract it, the system being capable of rapid shifts from one roller assembly to the other.

Still another object of the invention is a layout and construction ofa roller of the type involved in which its controls and operator positions are arranged for optimum operation and in which its structure is designed to accommodate the necessary functions and components of the roller in an efficient and economical manner,

SUMMARY OF THE INVENTION The roller of the present invention consists of a body fabricated essentially from pairs of spaced plates cut to form a body midportion and a pair of body end portions which are offset above the midportions. The end portions extend in opposite directions but over the two roller assemblies to which they are respectively pivoted in order to provide for steering of the roller. The body midportion houses an engine and hydraulic steering, drive and other pumps below a hood whose top wall forms a platform upon which the controls of the roller are placed. These include hydraulic steering and selection valves which control two pairs of rams alongside the body end portions connected to the respective roller assemblies so that the latter can be appropriately steered. The selection valve determines which of the two pairs of rams are in circuit with the steering valve and pump at a given time so that the two roller assemblies can be alternately steered. The steering valve is operated by a steering wheel atop a control shaft which angles up laterally from the valve. The latter valve is also pivoted to the control platform so that the steering wheel can be swung to either side of the roller within reach of the operator who sits atop one or the other of two pairs of tanks for fuel, hydraulic fluid and water cantilevered on the sidewalls of the body midportion between the two roller assemblies. This affords the operator an unobstructed view of the path of each roller assembly along the ground so that proper steering corrections can be readily made.

The roller assemblies are each propelled by varying the displacement of the drive pump, the control therefor also being located on the control platform with the steering and selection valves. The drive pump is in circuit with a hydraulic motor within each roller assembly which consists of a pair of rolls journaled independently of each other. The two motors drive a diagonally opposite pair of rolls of the two roller assemblies, with respect to the longitudinal axis of the roller, while the other diagonally opposite pair free-wheel, so to speak. The roller, of course, can be driven in either direction, its path being governed by steering either the leading or trailing one of the roller assemblies. Driving only one-half of each roller assembly while the other half free-wheels greatly reduces the tendency to scuff the bituminous mat surface during turns, the two rolls of each roller assembly acting to provide somewhat of a differential effect during turns as the roller proceeds. The fact that the two driven rolls are diagonally opposite assures that each half of the roller with respect to its longitudinal axis is equally driven and that in addition the couple action when the two roller assemblies are alternately turned to expand or contract the roller is stable and smooth in order to minimize scuffing. Once the proper width is reached one of the roller assemblies is locked in position by means of the selection valve and the direction of travel henceforth is controlled by steering the other only. The result is a roller of efficient layout and relatively simple construction that is readily adaptable to a wide range of paving jobs which would otherwise require more passes by a conventional roller or a multitude of rollers of different widths to accomplish.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of an expandable, articulated tandem roller according to the invention.

FIG. 2 is an end elevation of the roller of FIG. 1.

FIG. 3 is a top plan view of the roller of FIG. 1.

FIG. 4 is a partial isometric view of portions of the body and interior of the roller of FIG. 1 illustrating some of the essential features of its layout and construction.

FIG. 5 is a section view taken along the lines 55 of FIG. 2 illustrating the pivot of one roller assembly to the body.

FIG. 6 is a view partially in section taken along the line 6-6 of FIG. 1 illustrating the pivot of the other roller assembly to the body.

FIG. 7 is a section view taken along the line 7-7 of FIG. 6.

FIG. 8 is a section view along the line 88 of FIG. 3 illustrating details of the structure of one of the roller assemblies.

FIG. 9 is a schematic layout of the hydraulic system for propelling and steering the roller.

FIGS. 10A and 10B are diagrammatic views illustrating the steps involved in expanding and contracting the roller. respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIGS. 1 4, the body 10 of the roller consists essentially of a central or mid-portion and substantially identical opposite end portions all of whose side walls, collectively designated by 11, are fabricated from a series of plates. The latter form a pair of spaced mid-side walls 11a from which connecting side walls 11b angle upwards and are joined to end side walls 110 thereby offset above the mid-side walls 11a. The two pairs of end side walls 110 in turn are joined by end walls 11d having rounded noses, all of which are boxed in by floor and cover plates 12 and 13, respectively, the former being additionally braced by gusset plates 14. The end side walls 110 and the floor and cover plates 12 and 13 are joined by floor plates 15 and an upper surround of plates 16, the latter framing grilles 17. Similar grilles 18 are framed by a surround of plates 19 which join the floor plates 15 and the bottoms of the connecting side walls 11b in order to provide air and ventilation for an appropriate diesel engine E. The latter sits between the mid-side walls 11a atop a pair of beams 20 joining the latter and exhausts below through mufflers 21. The engine E drives a complex of pumps, generally designated at P, and is enclosed by a hood having a flat top wall and trapezoidal shaped side walls 31, fitted with grilles 32, abutting the upper edges of the side walls 11a and 11b. The hood top wall forms a control platform 33 just below the grilles 17 and adjoining the top edges of the four connecting side walls 11b. The hood 30 is hinged at 34 across one end of the control platform 33 to a plate 35 closing over the remainder of the adjacent pair of connecting sidewalls llb. The corresponding remainder of the other pair of connecting side walls 11b is closed over by an instrument panel 36 fitted with a cover 37 hinged to the adjacent end of the hood 30 which is lifted by handles 38 along its side walls 31. To the outer face of each mid- SltlC wall Ila is attached a trapezoidal shaped pair of supply tanks 40 for engine fuel. hydraulic fluid and water. The top walls of the tanks 40 include filler plugs 41 and are given non-skid surfaces in order to form operator platforms 42 abutting the lower edges of the hood side walls 31 below the control platform 33 and extending laterally outwards from the body side walls 11. Each of the two extremities of the body 10 is formed by a convergent nose section 45 in the nature of a sheet metal box attached to the adjacent end wall 11d and having an end face 46 carrying a pair of headlamps 47. It will be understood, of course, that construction of the foregoing is all chiefly by means of welding.

The two roller assemblies 50 are disposed beneath the ends of and support the body 10. Each roller assembly 50 includes a yoke consisting basically of a transverse beam 51 of box construction to whose ends is welded a pair of depending, tapered channels 52 whose lower ends embrace the outer ends of a pair of rolls RD and RF disposed end to end in axial alignment therebetween. Each beam 51 is pivoted at its midpoint to the body 10 about a vertical axis intersecting the longitudinal axis ofthe body 10 while one is additionally pivoted for rocking movement about an axis at right angles to the axis of the rolls RD and RF in order to accommodate different transverse slopes of the ground at the two ends of the roller. In the case of the former (see FIG. 5), a vertical spindle 53 is anchored to the top wall 51a of the beam 51 by means ofa tenon 53a at its lower end which is received in a collar 54a atop a larger collar 54b on the beam top wall 51a, all of the foregoing being secured by appropriate welds. The spindle 53 extends up through apertures in the floor and cover plates 12 and 13 of the end of the body 10 thereabove and is spacedly encompassed by a sleeve 55 between the plates 12 and 13. The lower end of the exterior of the sleeve 55 is shouldered at 56 to seat on the aperture in the floor plate 12 while its upper end projects through the cover plate 13 and is exteriorly shouldered to receive an annular gasket 57 over which is fitted an end cap 58. The interior of the sleeve is shouldered at 59 adjacent the floor plate 12 to receive the outer member of a bushing bearing 60 whose inner member abuts a shoulder 61 on the spindle 53 formed by necking down the remainder of the spindle 53 at 53b, all so as to resist upward loads on the spindle 53. The interior of the upper end of the sleeve 55 is also shouldered at 62 to receive the outer member of a complementary bushing bearing 63 whose inner member bears against a shoulder 64 formed by a further reduction of the spindle neck 53b at its upper end to which the end cap 58 is bolted at 65, all so as to resist downward loads on the spindle 53. The annular space 66 between the spindle neck 53a and the sleeve 55 is filled with suitable lubricant for the bearings 60 and 63 through suitable fittings. In the case of the roller assembly 50 at the other end of the body 10, the structure is similar (see FIGS. 6 and 7) except that the tenon 53a fits into a transverse pivot block 70 having ball ends 71 which are received in sockets 72 in a.

pair of cross blocks 73 welded to the beam top wall 51a across the ends of the pivot block 70 and which suspend the latter for rocking movement with respect to the beam 51. The cross blocks 73 are backed up by additional cross blocks 74 and by side blocks 75 across the ends of the cross blocks 73 and 74, all the latter having sufficient length to leave spaces 76 between the pivot block 70 and the side blocks 75 so that the former can rock. Finally, the cross blocks 74 and the ends of the side blocks 75 are welded to the opposed faces of a pair of round nosed plates 77 upstanding from and welded along the edges of the beam 51.

Each roller assembly is steered by means of a pair of hydraulic rams 80, the ends of whose cylinders are pivoted to clevis joints 81 supported in cup brackets 82 welded to the side walls 110. The rams extend forwardly and the outer ends of their piston rods 83 are pivoted in ball joint cleves 84 supported in similar brackets 85 welded to and upstanding from the forward edge of the adjacent yoke beam 51 on each side of its spindle 53. Referring now to FIG. 9 in particular, each pair of rams 80 is appropriately cross connected by hoses 86 to operate in push pull relation. Two pairs of lines 87 lead from the hoses 86 to two alternate positions of a shuttle type selection valve VS. From the latter a single pair oflines 88 leads to an orbital type steering or direction valve VD supplied with hydraulic fluid through a line 89a by a fixed displacement pump PS, one of the pump complex P. The pump PS draws from a hydraulic fluid reservoir R, constituting one of the tanks 40, through a line 90 and filter F1, the pump PS returning to the reservoir R through a companion line 89b from the valve VD. The steering valve VD is controlled by a steering column and wheel 91 and is pivoted to the control platform 33 so that it and the wheel 91 can be swung toward either operator platform 42. The operator himself sits in one of a pair of seats 92 swiveled atop pedestals 93 appropriately located on the operator platforms 42 with respect to the wheel 91 (see FIG. 3). The seats 92 are also pivoted to the pedestals 93 so that they can be upturned, so to speak, to protect them from weather elements when not in use, as shown in FIGS. 1 and 3. The selection valve VS is also mounted on the control platform 33 and provided with splayed levers 94 so that it can be operated from either seat 92. Finally, railings 95 enclose the four outer corners of the operator platforms 42, being anchored to the latter and to the body side walls 11c. To assist access to the control and operator platforms 33 and42 steps 96 are attached to the outer side wall of each pair of tanks 40 below and between the two pairs of adjacent corners of the railings 95.

Accordingly, as the steering wheel 92 is turned from its neutral position in either direction, fluid from the pump PS through the line 89a is directed by the steering valve VD into one or the other of the lines 88 and thence through the selection valve VS and one of the two lines 87 to the pair of the rams 80 then in circuit with the steering valve VD through the selection valve VS, the fluid from that pair of rams 80 being returned through the other of the two lines 87, the selection valve VS and the steering valve VD to the reservoir R through the line 89b. That pair of rams 80 in turn, owing to their push-pull operation, swings the yoke beam 51 and its spindle 53 in either direction to turn the roller assembly 50 concerned and so steer that end of the roller. When the operator wishes to steer the other end of the roller, he shifts the selection valve VS with the levers 94 so that the other pair of rams is in circuit with the steering valve VD. Hence, the two ends of the roller are alternately steered. Note that the selection valve VS provides in effect a hydraulic lock for the pair oframs 80 not in circuit with the steering valve VD at the time so as to fix the position of one roller assembly 50 when the other is being steered.

Returning to each roller assembly 50 and referring now to FIG. 8 in particular, the rolls RF and RD consist essentially of outer cylindrical shells 100 of equal length disposed to the sides of the longitudinal axis of the body 10. The shells 100 closely abut each other in axial alignment between the yoke legs 52, and include respective outer and inner end walls 101a, 1011;, 1010 and 101d. The end walls 101a, 1011) and 1010 are axially apertured to receive a shaft 102, one of whose ends extends through the yoke leg 52 adjacent the end wall 101a and is anchored thereto at 103 so that the shaft 102 cannot rotate. The shaft 102 extends through the roll RF and well into the roll RD and upon it are mounted four sets of tapered roller bearings 104a, 104b, and 104C and 104d, the bearing 104a being positioned adjacent the end wall 101a and axially located in one direction by a lipped bushing 105a through and fixed to the roll end wall 101a. The bearing 1040 is axially located in the other direction by a spacer sleeve 106 between it and the anchor 103, and an annular seal 107 surrounds the sleeve 106 and is bolted at 108 to the exposed end of the bushing 105a. The two bearings 104b and 104C are positioned at the respective inner roll end walls 101!) and 101c and are axially located on the shaft 103 in respective opposite directions by similar lipped bushings 105b and 1056 through and fixed to the respective inner end walls 101b and l01c, the two bearings 104b and 1046 being located in their other respective axial directions by a spacer sleeve 109 therebetween on the shaft 102. The remaining bearing 104d is positioned on the other end of the shaft 102 within the roll RD and located in one axial direction by another lipped bushing 105d whose outer end is extended beyond the end of the shaft 102 and closed by an end plate 110 bolted thereto at 111. Beneath the end plate 110 another end plate 112 is bolted at 113 to the end of the shaft 102 to locate the bearing 104d in the other direction. From the periphery of the bushing 105d a series of six equally spaced struts 114 (only two being shown) angle out therefrom and are welded at their outer ends to the juncture of the shell 100 and end wall 101d of the roll RD. The latter end wall is also axially apertured to receive the cylindrical casing 115 of a low speed, high torque hydraulic motor MD which is located just outboard of the end plate 110, in axial alignment with the shaft 102, and provided with a flange 116 which is bolted at 117 to the outer face of the end wall 101d. The inner member 118 of the motor MD is bolted at 119 to the adjacent yoke leg 52, whereby the two rolls RF and RD are supported by the shaft 102 and the motor MD. The latter is of the well known type, such as is sold under the trademark TRANS-WHEEL, in which the outer casing 115 is driven for rotation while the inner member 118 is stationary. Hence the two rolls RF are free to rotate on their shafts 102 by virtue of their bearings 104a and 104b wholly independently of the two rolls RD which are each driven relative to the shafts 102 by the motors MD through their casings 115 and the roll end walls 101d and bearings 104a and 104d. In order to stiffen the support of the rolls RF and RD between the yoke legs 52, the bushings 105a and 10512, 1050 and 105d are respectively joined by sleeves 120 which spacedly encompass the shaft 102 and additionally provide sealed annular reservoirs 121 for lubricant for the bearings 104. The outer roll end walls 101a and 101d are provided with suitable plugs 122 so that the rolls RD and RF can be filled with water for weight. Finally, as will be observed from FIGS. 1 and 3, the rolls are arranged so that the driven and free rolls RD and RF of the two roller assemblies 50 are respectively diagonally opposite each other with respect to the longitudinal axis of the body 10.

Returning again to FIG. 9, the hydraulic circuit for the drive rolls RD is of the closed loop design and includes a reversible, servo controlled, variable displacement pump PD, also part of the pump complex P, whose makeup pump draws from the reservoir R through a line 130 and filter F2, its makeup pump relief PR and case drain returning to the reservoir R through lines 131 and 132, respectively, the former through a cooler C. The alternate pump output and return lines 133 and 134 lead into opposite sides of a Tee block TB adjacent the pump PD in which respective passages 135, 136 lead off into a relief block RB containing high pressure reliefs 135a and 136a, which alternately return to the suction side of the pump PD, and a low pressure relief 137, the latter being connected by a line 138 into the line 131 upstream of the cooler C for return to the reservoir R. Each line 133 and 134 bifurcates as it passes through the Tee block TB and both emerge as two pairs of lines 140a, 141a and 140b, 141b, respectively. The two lines 140a, 141a and the two lines 140b, l41b pass out of the body through its respective floor plates 15, thence through flexible hoses (see FIGS. 1 and 3) to the yoke beam top walls 51a adjacent the spindles 53, along the top walls 51a and down the yoke legs 52 beneath hat shaped covers 142, and finally through the yoke legs 52 to the inner members 118 of the motors MD (sec FIGS. 1, 2, and 3). The lines 140a, 141a and 14017, 141b function respectively and alternately as supply and return lines for the motors MD depending upon the direction in which they are driven by the pump PD, the casings of the two motors MD being drained by lines 143 connected into the line 131 upstream of the cooler C for return to the reservoir R. The servo S, which strokes the pump PD from neutral to drive in either of its two directions, is also operated by splayed levers 145 placed on the control platform 33 with the selection valve levers 94 for convenient operation from either of the seats 92 (see FIG. 3). Hence when the levers 145 are moved from neutral one way or the other the motors MD drive the two rolls RD and thus the roller in either direction of travel. It will be understood that each roller assembly 50 would be equipped with suitable spray bars (not shown) to wet the roll shells 100 and cocoa mats (not shown) across and in contact with the latter to retain moisture, all as is typical. The spray bars are supplied by a water pump (not shown), another part of the pump complex P, controlled by suitable switches 146 also adjacent the two seats 92 betwcen which are placed the essential controls 147 for the engine E. It will also be understood that the connections to the steering valve VD, selection valve VS, servo S, and controls 146 and 147 are all flexiblc so that they can be lifted together with the hood 30 when the latter is raised for access to the engine E, pumps P and the interior of the body 10. Each roll RD may also be equipped with a suitable parking brake 148 (see FIG. 1), mechanically operated from one of the operator platforms 42, which acts against a disc (not shown) carried by the adjacent roll end wall 101d.

As illustrated in FIG. 3, the roller assemblies 50 are, of course, in their tandem position. In this mode, the roller can be driven in either direction by the drive levers 145 and either roller assembly 50 steered by the wheel 91 depending upon the position of the selection valve levers 94. Referring now to FIGS. 10A and 108, one method of expanding the roller involves first turning it in the desired direction of expansion by, say, the leading roller assembly 50, halting it with the drive levers 145, and turning first one roller assembly 50 and then the other by means of the wheel 91 and the selection valve levers 94 to the proper angles, all as shown in the mid-part of FIG. 10A. In order to help establish those angles, the end caps 58, which rotate with the spindles 53, and cover plates 13 of the body 10 are provided with suitable indicia 149 (see FIG. 3). The drive levers are then moved to propel the roller whereupon, owing to the resulting couple action, the roller assemblies 50, now in echelon relation to each other, proceed in the direction of travel with the body 10 in a canted or angled relation to that direction. Thenceforth, the roller is steered normally by either the leading or trailing roller assembly 50, the other remaining locked in position. Contraction of the roller is achieved by a like procedure as shown in FIG. 103. The diagonally opposite drive rolls RD and free wheel rolls RF reduce scuffing to a minimum when either roller assembly 50 is turned and in particular assure a smooth, stable couple action with little or no scuffing when the roller is expanded or contracted. Note that the operator sits well off to either side of the body 10 with a virtually unobstructed view of each roller assembly 50 so that the roller can be precisely steered along the edge of a mat at either side. The control levers 94 and 145 fall readily to hand no matter on which side of the roller the operator sits; indeed, they could be placed on a pivoted column of their own to be swung from side to side with the steering wheel 91, or could even be put on the steering column itself.

Though the present invention has been described in terms of a particular embodiment, being the best mode known of carrying out the invention, it is not limited to that embodiment alone. Instead, the following claims are to be read as encompassing all adaptations and modifications of the invention falling within its spirit and scope.

We claim:

1. A self-propelled roller comprising: a body assembly; a ground engaging roller assembly disposed at each of two spaced locations on and supporting the body assembly, both of the roller assemblies being articulated at said locations with respect to the body assembly for dirigible movement effective to determine the direction of travel of the roller, each of the roller assemblies including at least one pair of rotable, axially aligned rolls disposed on respective opposite sides of an axis of the body assembly through said locations and drive means for propelling said roller assembly along the ground, the drive means of the two roller assemblies being respectively operable upon one pair of diagonally opposite rolls thereof with respect to said axis, another pair of diagonally opposite rolls of the two roller assemblies with respect to said axis being undriven and rotable independently of the first pair; and means for controlling the dirigible movement of each roller assembly with respect to the body assembly effective to provide selective adjustment of the two roller assemblies between tandem and echelon positions with respect to each other and the direction of travel of the roller.

2. The roller of claim 1 wherein the body assembly includes a central portion and end portions extending in opposite directions from the central portion out over the respective roller assemblies, the roller assemblies being pivoted to their respective end portions to constitute the two spaced locations at which the roller assemblies are articulated with respect to the body assembly, the central body portion carrying fluid holding tanks and power means for driving the two drive means of the roller assemblies.

3. The roller of claim 2 wherein the central body por' tion and the end portions include a pair of spaced plates extending longitudinally of the body assembly and forming side walls of the central and end portions, the end portion side walls being offset above the central portion side walls and connected thereto by inclined portions of the side plates, the power means being mounted between the central portion side walls, and including a hood extending between the end portions and the central portion side walls effective to close over the central body portion, the hood having a top wall forming a control platform and carrying the control means.

4. The roller of claim 3 wherein the fluid holding tanks are cantilevered on each central portion side wall and include top walls disposed laterally outwards of the control platform having operator seats thereon located between the roller assemblies and in operative relation to the control means.

5. The roller of claim 4 wherein the hood is hinged to the body assembly about a transverse axis with respect to the longitudinal axis of the body assembly for upward movement thereof together with the control means for access to the power means and the interior of the central body portion.

6. The roller of claim 1 wherein each roller assembly includes a yoke assembly having legs embracing the outer axial ends of the rolls of the roller assembly, the rolls being connected to the legs by a roll supporting assembly coaxial with the rolls and providing for rotation of the rolls with respect to the yoke, at least one of the rolls being journaled on the supporting assembly for rotation independently of the other rolls thereof.

7. The roller of claim 6 wherein the drive means drives said journaled roll.

8. The roller of claim 7 wherein the supporting assembly includes the drive means, the drive means being a fluid motor.

9. The roller of claim 6 wherein the supporting assembly comprises stationary portions and rotation portions, the rotating portions including a rotating portion of the drive means driving one of the rolls.

10. The roller of claim 9 wherein the stationary portions of the supporting assembly include a shaft upon which all of the rolls are journaled for rotation with respect thereto.

11. The roller of claim 1 wherein the control means is selectively operable upon alternate ones of the two roller assemblies.

12. The roller of claim 11 wherein the control means includes fluid pump means, fluid power means operatively associated with each roller assembly and a selection valve having alternate positions for selectively directing fluid to alternate ones of the two fluid power means.

L. The roller of claim 12 wherein the fluid power means for each roller assembly comprises a pair of steering rams, alternate pairs of the rams being in fluid circuit with the pump means through the alternate positions of the selection valve.

14. The roller of claim 13 including a steering valve in fluid circuit with the pump means, the selection valve and alternate pairs of the steering rams when the selection valve is in alternate ones of its positions, the steering valve being operable through successive positions thereof effective to direct fluid flow from the pump means in alternate directions through the circuit to one pair of the steering rams when the selection valve is in one of its alternate positions connecting said pair of rams in circuit with the pump means.

15. The roller of claim 14 wherein the body assembly includes an intermediate housing between the two roller assemblies and a pair of end housings extending from the intermediate housing in opposite directions out over respective ones of the roller assemblies, the intermediate and end housings having opposite side walls extending longitudinally of the body assembly, each of the roller assemblies including a beam extending above and axially parallel to the rolls thereof, the central portion of the beam having a pivot with its respective end housing effective to provide said articulation of the roller assembly with respect to the body assembly, and wherein each pair of the steering rams extends from respective ones of the body assembly side walls to one of said beams at respective locations on opposite sides of said pivot.

16. The roller of claim 15 wherein each roller assembly includes two rolls having their outer axial ends embraced by a pair of legs depending from said beam, the rolls being connected to the legs by a roll supporting assembly coaxial with the two rolls and providing for rotation of both of the two rolls with respect to the legs, at least one of the two rolls being journaled on the supporting assembly for rotation independently of the other of the two rolls.

17. The roller of claim 16 wherein the drive means for said roller assembly comprises a fluid motor in fluid circuit with the pump means, the motor having stationary and rotating portions and forming a portion of the supporting assembly, the rotating motor portion driving one of the two rolls.

18. The roller of claim 17 wherein the pump means and engine for driving the pump means are disposed beneath a top wall of the intermediate housing forming a control platform, the selection and steering valves being mounted on the platform, and wherein the steering valve includes a control shaft for operating the steering valve as aforesaid, the shaft angling upwards from the steering valve and the platform in a lateral direction toward one of the intermediate housing side walls and fitted with a manually operable steering wheel at its upper end, the steering valve being pivoted with respect to the platform effective so that the valve, control shaft and steering wheel can be manually moved to angle up from the platform toward the other intermediate housing side wall.

19. The roller of claim 18 including engine fuel and hydraulic fluid supply tanks disposed laterally outward of the intermediate housing side walls, the tanks including top walls forming operator platforms disposed along opposite sides of the control platform and between the roller assemblies laterally outboard of the body assembly side walls, the operator platform carrying operator seats operatively disposed with respect to the steering wheel and the selection valve.

20. The roller of claim 19 wherein the control platform is pivoted to the body assembly for upward movement together with the selection and steering valves for access to the engine and the pump means.

21. A self-propelled roller comprising: a body assembly and a pair of ground engaging roller assemblies supporting the body assembly, the body assembly including a central portion and end portions extending in opposite directions from the central portion, the two roller assemblies being pivoted to respective ones of the end portions for dirigible movement effective to determine the direction of travel of the roller, each of the roller assemblies including at least a pair of axially aligned rolls rotable with respect to each other disposed on respective sides of a longitudinal axis of the body assembly through said pivots and motor means for propelling at least one pair of the rolls of the two roller assemblies on diagonally opposite sides of said axis and thereby the roller along the ground, and power steering means for controlling the dirigible movement of each roller assembly with respect to the body assembly effective to provide selective adjustment of the two roller assemblies between tandem and echelon positions with respect to each other and the direction of travel of the roller, the body assembly carrying fluid holding tanks and a power source for the motor means of the roller assemblies and the power steering means.

22. The roller of claim 21 wherein the body assembly includes side walls extending longitudinally of said axis, the end portion side walls being offset above the central portion side walls, the power source being mounted between the central portion side walls, and including a hood between the central portion side walls effective to close over the central body portion, the hood having a top wall forming a control platform and carrying control means for the motor means and the power steering means.

23. The roller of claim 22 wherein the fluid holding tanks are cantilevered on each central portion side wall and include top walls disposed laterally outwards of the control platform having operator positions thereon loeated between the roller assemblies and in operative relation to the control means.

24. The roller of claim 23 wherein the hood is hinged to the body assembly about a transverse axis with respect to the longitudinal axis of the body assembly for upward movement thereof together with the control means for access to the power source and the interior of the central body portion.

25. The roller of claim 21 wherein the power source comprises an engine, and wherein the power steering means includes a fluid pump means driven by the engine. fluid power means operatively associated with each rollerassembly and a selection valve having alternate positions for selectively directing fluid to alternate ones of the fluid power means.

26. The roller of claim 25 wherein the fluid power means for each roller assembly comprises a pair of steering rams, alternate pairs of the rams being in fluid circuit with the pump means through the alternate positions of the selection valve.

27. The roller of claim 26 including a steering valve in fluid circuit with the pump means, the selection valve and alternate pairs of the steering rams when the selection valve is in alternate ones of its positions, the steering valve being operable through successive positions thereof effective to direct fluid flow from the pump means in alternate directions through the circuit to one pair of the steering rams when the selection valve is in the one of its alternate positions connecting said pair of rams in circuit with the pump means.

28. The roller of claim 25 wherein the motor means for the roller assemblies comprise fluid motors in fluid circuit with the pump means, the pump means and the engine being disposed beneath atop wall of the central body portion forming a control platform between opposite side walls of the central body portion extending longitudinally of said axis, and wherein the power steering means includes a steering valve carried together with the selection valve by the control platform, the steering valve having a control shaft angling upwards from the steering valve and the platform in a lateral direction toward one of said side walls and fitted with a manually operable steering wheel at its upper end, the steering valve being pivoted with respect to the platform effective so that the valve, control shaft and steering wheel can be manually moved to angle up from the platform laterally toward the other of said side walls.

29. The roller of claim 28 wherein the fluid holding tanks include engine fuel and hydraulic fluid supply tanks disposed laterally outward of the side walls of the central body portion, the tanks including top walls forming operator platforms disposed along opposite side edges of the control platform and between the roller assemblies laterally outboard of the body assembly, the operator platform carrying operator seats operatively disposed with respect to the steering wheel and the selection valve.

30. The roller of claim 29 wherein the control platform is pivoted to the body assembly for upward movement together with the selection and steering valves for access to the engine and the pump means. 

1. A self-propelled roller comprising: a body assembly; a ground engaging roller assembly disposed at each of two spaced locations on and supporting the body assembly, both of the roller assemblies being articulated at said locations with respect to the body assembly for dirigible movement effective to determine the direction of travel of the roller, each of the roller assemblies including at least one pair of rotable, axially aligned rolls disposed on respective opposite sides of an axis of the body assembly through said locations and drive means for propelling said roller assembly along the ground, the drive means of the two roller assemblies being respectively operable upon one pair of diagonally opposite rolls thereof with respect to said axis, another pair of diagonally opposite rolls of the two roller assemblies with respect to said axis being undriven and rotable independently of the first pair; and means for controlling the dirigible movement of each roller assembly with respect to the body assembly effective to provide selective adjustment of the two roller assemblies between tandem and echelon positions with respect to each other and the direction of travel of the roller.
 2. The roller of claim 1 wherein the body assembly includes a central portion and end portions extending in opposite directions from the central portion out over the respective roller assemblies, the roller assemblies being pivoted to their respective end portions to constitute the two spaced locations at which the roller assemblies are articulated with respect to the body assembly, the central body portion carrying fluid holding tanks and power means for driving the two drive means of the roller assemblies.
 3. The roller of claim 2 wherein the central body portion and the end portions include a pair of spaced plates extending longitudinally of the body assembly and forming side walls of the central and end portions, the end portion side walls being offset above the central portion side walls and connected thereto by inclined portions of the side plates, the power means being mounted between the central portion side walls, and including a hood extending between the end portions and the central portion side walls effective to close over the central body portion, the hood having a top wall forming a control platform and carrying the control means.
 4. The roller of claim 3 wherein the fluid holding tanks are cantilevered on each central portion side wall and include top walls disposed laterally outwards of the control platform having operator seats thereon located between the roller assemblies and in operative relation to the control means.
 5. The roller of claim 4 wherein the hood is hinged to the body assembly about a transverse axis with respect to the longitudinal axis of the body assembly for upward movement thereof together with the control means for access to the power means and the interior of the central body portion.
 6. The roller of claim 1 wherein each roller assembly includes a yoke assembly having legs embracing the outer axial ends of the rolls of the roller assembly, the rolls being cOnnected to the legs by a roll supporting assembly coaxial with the rolls and providing for rotation of the rolls with respect to the yoke, at least one of the rolls being journaled on the supporting assembly for rotation independently of the other rolls thereof.
 7. The roller of claim 6 wherein the drive means drives said journaled roll.
 8. The roller of claim 7 wherein the supporting assembly includes the drive means, the drive means being a fluid motor.
 9. The roller of claim 6 wherein the supporting assembly comprises stationary portions and rotation portions, the rotating portions including a rotating portion of the drive means driving one of the rolls.
 10. The roller of claim 9 wherein the stationary portions of the supporting assembly include a shaft upon which all of the rolls are journaled for rotation with respect thereto.
 11. The roller of claim 1 wherein the control means is selectively operable upon alternate ones of the two roller assemblies.
 12. The roller of claim 11 wherein the control means includes fluid pump means, fluid power means operatively associated with each roller assembly and a selection valve having alternate positions for selectively directing fluid to alternate ones of the two fluid power means.
 13. The roller of claim 12 wherein the fluid power means for each roller assembly comprises a pair of steering rams, alternate pairs of the rams being in fluid circuit with the pump means through the alternate positions of the selection valve.
 14. The roller of claim 13 including a steering valve in fluid circuit with the pump means, the selection valve and alternate pairs of the steering rams when the selection valve is in alternate ones of its positions, the steering valve being operable through successive positions thereof effective to direct fluid flow from the pump means in alternate directions through the circuit to one pair of the steering rams when the selection valve is in one of its alternate positions connecting said pair of rams in circuit with the pump means.
 15. The roller of claim 14 wherein the body assembly includes an intermediate housing between the two roller assemblies and a pair of end housings extending from the intermediate housing in opposite directions out over respective ones of the roller assemblies, the intermediate and end housings having opposite side walls extending longitudinally of the body assembly, each of the roller assemblies including a beam extending above and axially parallel to the rolls thereof, the central portion of the beam having a pivot with its respective end housing effective to provide said articulation of the roller assembly with respect to the body assembly, and wherein each pair of the steering rams extends from respective ones of the body assembly side walls to one of said beams at respective locations on opposite sides of said pivot.
 16. The roller of claim 15 wherein each roller assembly includes two rolls having their outer axial ends embraced by a pair of legs depending from said beam, the rolls being connected to the legs by a roll supporting assembly coaxial with the two rolls and providing for rotation of both of the two rolls with respect to the legs, at least one of the two rolls being journaled on the supporting assembly for rotation independently of the other of the two rolls.
 17. The roller of claim 16 wherein the drive means for said roller assembly comprises a fluid motor in fluid circuit with the pump means, the motor having stationary and rotating portions and forming a portion of the supporting assembly, the rotating motor portion driving one of the two rolls.
 18. The roller of claim 17 wherein the pump means and engine for driving the pump means are disposed beneath a top wall of the intermediate housing forming a control platform, the selection and steering valves being mounted on the platform, and wherein the steering valve includes a control shaft for operating the steering valve as aforesaid, the shaft angling upwards from the steering valve and thE platform in a lateral direction toward one of the intermediate housing side walls and fitted with a manually operable steering wheel at its upper end, the steering valve being pivoted with respect to the platform effective so that the valve, control shaft and steering wheel can be manually moved to angle up from the platform toward the other intermediate housing side wall.
 19. The roller of claim 18 including engine fuel and hydraulic fluid supply tanks disposed laterally outward of the intermediate housing side walls, the tanks including top walls forming operator platforms disposed along opposite sides of the control platform and between the roller assemblies laterally outboard of the body assembly side walls, the operator platform carrying operator seats operatively disposed with respect to the steering wheel and the selection valve.
 20. The roller of claim 19 wherein the control platform is pivoted to the body assembly for upward movement together with the selection and steering valves for access to the engine and the pump means.
 21. A self-propelled roller comprising: a body assembly and a pair of ground engaging roller assemblies supporting the body assembly, the body assembly including a central portion and end portions extending in opposite directions from the central portion, the two roller assemblies being pivoted to respective ones of the end portions for dirigible movement effective to determine the direction of travel of the roller, each of the roller assemblies including at least a pair of axially aligned rolls rotable with respect to each other disposed on respective sides of a longitudinal axis of the body assembly through said pivots and motor means for propelling at least one pair of the rolls of the two roller assemblies on diagonally opposite sides of said axis and thereby the roller along the ground, and power steering means for controlling the dirigible movement of each roller assembly with respect to the body assembly effective to provide selective adjustment of the two roller assemblies between tandem and echelon positions with respect to each other and the direction of travel of the roller, the body assembly carrying fluid holding tanks and a power source for the motor means of the roller assemblies and the power steering means.
 22. The roller of claim 21 wherein the body assembly includes side walls extending longitudinally of said axis, the end portion side walls being offset above the central portion side walls, the power source being mounted between the central portion side walls, and including a hood between the central portion side walls effective to close over the central body portion, the hood having a top wall forming a control platform and carrying control means for the motor means and the power steering means.
 23. The roller of claim 22 wherein the fluid holding tanks are cantilevered on each central portion side wall and include top walls disposed laterally outwards of the control platform having operator positions thereon located between the roller assemblies and in operative relation to the control means.
 24. The roller of claim 23 wherein the hood is hinged to the body assembly about a transverse axis with respect to the longitudinal axis of the body assembly for upward movement thereof together with the control means for access to the power source and the interior of the central body portion.
 25. The roller of claim 21 wherein the power source comprises an engine, and wherein the power steering means includes a fluid pump means driven by the engine, fluid power means operatively associated with each roller assembly and a selection valve having alternate positions for selectively directing fluid to alternate ones of the fluid power means.
 26. The roller of claim 25 wherein the fluid power means for each roller assembly comprises a pair of steering rams, alternate pairs of the rams being in fluid circuit with the pump means through the alternate positions of the selection valve.
 27. The roller of claim 26 inCluding a steering valve in fluid circuit with the pump means, the selection valve and alternate pairs of the steering rams when the selection valve is in alternate ones of its positions, the steering valve being operable through successive positions thereof effective to direct fluid flow from the pump means in alternate directions through the circuit to one pair of the steering rams when the selection valve is in the one of its alternate positions connecting said pair of rams in circuit with the pump means.
 28. The roller of claim 25 wherein the motor means for the roller assemblies comprise fluid motors in fluid circuit with the pump means, the pump means and the engine being disposed beneath a top wall of the central body portion forming a control platform between opposite side walls of the central body portion extending longitudinally of said axis, and wherein the power steering means includes a steering valve carried together with the selection valve by the control platform, the steering valve having a control shaft angling upwards from the steering valve and the platform in a lateral direction toward one of said side walls and fitted with a manually operable steering wheel at its upper end, the steering valve being pivoted with respect to the platform effective so that the valve, control shaft and steering wheel can be manually moved to angle up from the platform laterally toward the other of said side walls.
 29. The roller of claim 28 wherein the fluid holding tanks include engine fuel and hydraulic fluid supply tanks disposed laterally outward of the side walls of the central body portion, the tanks including top walls forming operator platforms disposed along opposite side edges of the control platform and between the roller assemblies laterally outboard of the body assembly, the operator platform carrying operator seats operatively disposed with respect to the steering wheel and the selection valve.
 30. The roller of claim 29 wherein the control platform is pivoted to the body assembly for upward movement together with the selection and steering valves for access to the engine and the pump means. 